System for controlling fluid flow

ABSTRACT

A system for controlling fluid flow to or from a cylinder of an internal combustion engine is disclosed. The system includes a drive shaft having a rotary valve mounted thereon. The system also includes a cylinder head a cylinder head accommodating the rotary valve and at least part of the drive shaft therein, the rotary valve being arranged to selectively open or close a flow opening in the cylinder head. The system also includes a source of rotation and a mechanical drive train rotatably coupling the source of rotation to the drive shaft. The mechanical drive train has a non-circular element rotatably coupled to the source of rotation and a non-circular element rotatably coupled to the drive shaft. The non-circular elements are rotatably coupled to cause a speed variation in one of the non-circular elements upon a constant rotation of the other non-circular elements.

This application claims the benefit of U.S. Provisional Application No.60/877,372, filed Dec. 28, 2006.

TECHNICAL FIELD

This disclosure relates generally to internal combustion engines andmore specifically to a system and a method for controlling fluid flow toor from a cylinder of the internal combustion engine.

BACKGROUND

Internal combustion engines typically have a main body forming cylindersand a cylinder head for closing one end of cylinders. The cylinders,pistons reciprocating in the cylinders, and the cylinder head define acombustion chamber having a variable volume therebetween. A valve isarranged in the internal combustion engine, to provide one of a flow ofair and a mixture of air and fuel into the combustion chamber. Typicallya separate valve is arranged in the cylinder head to provide exhaustingof exhaust gases from the combustion chamber.

In most internal combustion engines poppet valves are used to controlthe inflow and outflow of gases into the combustion chamber. Thesepoppet valves are typically activated by a camshaft, which is rotatablycoupled by a drive element to a crankshaft of the internal combustionengine. The rotatable coupling of the crankshaft to the camshaftprovides a constant ratio between the speed of rotation of thecrankshaft and the speed of rotation of the camshaft. The activation ofthe individual valves is thus fixed to the rotation of the crankshaft.No independent control of the valves is possible even if it is desiredto achieve improved engine performance and/or emission characteristics.

The poppet valves are typically spring biased to a closed positionthereof. To open the valve, the camshaft has to first overcome the biasof the springs, which leads to large energy expenditure for opening ofthe valves.

An alternative internal combustion engine using spherical rotary intakeand outlet valves in a cylinder head is shown in U.S. Pat. No.6,779,504, issued to Coates on Aug. 24, 2004. The Coates cylinder headis formed by two separate body portion. The body portions when assembledto each other define a plurality of spherical valve chambers eachconformed to the shape of a single spherical valve to be accommodatedtherein. The spherical rotary valves are mounted to a drive shaft, whichis rotatably coupled to the crankshaft of the internal combustionengine. The rotatable coupling of the crankshaft to the camshaft againprovides a constant ratio between the speed of rotation of thecrankshaft and the speed of rotation of the camshaft.

Flow of air between the cylinder head and the cylinder is controlled byeach of the spherical rotary valves accommodated in the cylinder head.In particular, flow of gases is allowed through an opening in thespherical surface of the rotary valve, which is brought into alignmentwith a flow opening in the lower body part of the cylinder head, andthrough the side surfaces of the spherical rotary valves.

At the beginning of a valve opening event, the flow through the rotaryvalve increases gradually. Similarly, at the end of an opening event,the flow through the rotary valve decreases gradually. A fast openingand closing would, however, be desired to optimize the flow of gasesthrough the rotary valves.

The present application is directed to overcoming one or more of theproblems set forth above.

SUMMARY

In one aspect, the present disclosure is directed to a system forcontrolling fluid flow to or from a cylinder of an internal combustionengine. The system may include a drive shaft having a rotary valvemounted thereon. A cylinder head may be provided to accommodate therotary valve and at least part of the drive shaft therein. The rotaryvalve may be arranged in the cylinder head to selectively open or closea flow opening therein. The system may also include a source of rotationand a mechanical drive train rotatably coupling the source of rotationto the drive shaft. The mechanical drive train may have a non-circularelement rotatably coupled to the source of rotation and a non-circularelement rotatably coupled to the drive shaft. The non-circular elementsmay be rotatably coupled to cause a speed variation in one of thenon-circular elements upon a constant rotation of the other non-circularelements.

In another aspect, the present disclosure is directed to a method forcontrolling fluid flow to or from a cylinder of an internal combustionengine. The method may include rotating a rotary valve accommodated in acylinder head associated with the cylinder. The rotary valve may bearranged in the cylinder head to selectively open or close a flowopening therein. Additionally, the speed of rotation of the rotary valvemay be varied during a single rotation thereof between at least twodifferent speeds.

In yet another aspect, the present disclosure is directed to a systemfor controlling fluid flow to or from a cylinder of an internalcombustion engine. The system may include a drive shaft having a rotaryvalve mounted thereon. A cylinder head may be provided to accommodatethe rotary valve and at least part of the drive shaft therein. Therotary valve may be arranged in the cylinder head to selectively open orclose a flow opening therein. The system may also include a source ofrotation and a mechanical drive train rotatably coupling the source ofrotation to the drive shaft. The mechanical drive train may include anon-circular element rotatably coupled to one of the source of rotationand the drive shaft and a circular element rotatably coupled to theother one of the drive shaft and the source of rotation. Thenon-circular element and the circular element may be rotatably coupledto cause a speed variation in one of the non-circular and circularelements upon a constant rotation of the other.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of parts of an internal combustion enginehaving an exemplary cylinder head;

FIG. 2 is a perspective view of the cylinder head of FIG. 1;

FIG. 3 is a top view of the cylinder head of FIG. 2;

FIG. 4 is a perspective view showing the bottom of the cylinder head ofFIG. 1;

FIG. 5 is a perspective showing the top of the cylinder head of FIG. 1,having a cover plate mounted thereon;

FIG. 6 is a cross-sectional view of the cylinder head along line VI-VIin FIG. 3, having additional elements mounted therein;

FIG. 7 is a cross-sectional view along line VII-VII in FIG. 6;

FIG. 8 is a cross-sectional view along line VIII-VIII in FIG. 7;

FIG. 9 is a partial top view of the cylinder head of FIG. 2, havingrotary valves arranged therein;

FIG. 10 is an end view of an alternative cylinder head;

FIG. 11 is a top view of an exemplary rotary valve to be used in acylinder head of an internal combustion engine;

FIG. 12 is a cross-sectional view of the rotary valve along line B-B inFIG. 11;

FIG. 13 is a side view of the rotary valve of FIG. 11;

FIG. 14 is a cross-sectional view of the rotary valve along line A-A inFIG. 11;

FIG. 15 is another side view of the rotary valve of FIG. 11;

FIG. 16 is perspective view of the rotary valve of FIG. 11;

FIG. 17 is cross-sectional view similar to FIG. 14 of an alternativerotary valve;

FIG. 18 is cross-sectional view similar to FIG. 12 of an alternativerotary valve;

FIG. 19 is cross-sectional view of a drive shaft for rotating rotaryvalves;

FIG. 20 is an enlarged cross-sectional view of a section of the driveshaft according to FIG. 19, having a rotary valve mounted thereon;

FIG. 21( a) is a cross-sectional view of a deflector/bearing assembly;

FIG. 21( b) is a cross-sectional view of an alternativedeflector/bearing assembly;

FIG. 22 is a cross-sectional view of a deflector assembly;

FIG. 23 is a schematic end view of an internal combustion engine showinga drive mechanism for driving rotary valves arranged in the cylinderhead of the internal combustion engine;

FIG. 24( a) is an end view of an internal combustion engine;

FIG. 24( b) is a top view of an internal combustion engine, showing analternative drive mechanism for driving rotary valves arranged withinthe cylinder head of the engine;

FIG. 25 is an end view of an internal combustion engine showing anotheralternative drive mechanism for driving rotary valves arranged withinthe cylinder head of the combustion engine;

FIG. 25( a) is an end view of an internal combustion engine showinganother alternative drive mechanism for driving rotary valves arrangedwithin the cylinder head of the combustion engine;

FIG. 26( a) is an end view of an internal combustion engine;

FIG. 26( b) is a top view of an internal combustion engine; and

FIG. 26( c) is an enlarged schematic cross-sectional view through adrive motor; wherein a further alternative drive mechanism for drivingrotary valves arranged within the cylinder head is shown.

DETAILED DESCRIPTION

In the following description, relative terms such as top, bottom, side,left, right, etc., may be used to describe certain elements. Theserelative terms are used for descriptive purposes only and should not beconstrued to limit the application. In the following, a flow area willbe specified for openings and passages, etc. In these instances the term“flow area” will relate to the smallest cross sectional area of theopening, passage, etc.

Reference signs are used in the following description and drawings todescribe the examples shown in the drawings. Throughout the differentviews and examples, the same reference signs may be used to designatesimilar parts.

FIG. 1 shows a perspective view of an internal combustion engine 1 inaccordance with an embodiment of the application. For simplification, anengine main body 3 and crankshaft housing 4 are only schematicallyshown, while a cylinder head 7 of the engine 1 is shown in more detail.As one of ordinary skill would recognize, engine main body 3 may have atleast one cylinder (not shown) formed therein, for accommodating acorresponding number of pistons therein. The exemplary engine main body3 shown in FIG. 1 has four cylinders formed therein. The presentapplication, however, is not limited to an engine having four cylinders.

The crankshaft housing 4 is adapted to accommodate a crankshaft which iscoupled to the pistons as is known in the art. The crankshaft housing 4has an opening 9 in at least one end thereof to allow part of thecrankshaft to extend outside of the crankshaft housing 4.

The cylinder head 7 will now be described in more detail with respect toFIGS. 2-9 of the drawings which show an exemplary cylinder head. Thecylinder head 7 includes a single piece cylinder main body 11 and acover plate 12 which is best shown in FIG. 5. The cylinder main body 11has a top surface 15 (best seen in FIGS. 2 and 3), a bottom surface 16(best seen in FIG. 4), opposite end faces 17 and 18 (best seen in FIGS.4 and 5), and opposite sides 19, 20 (best seen in FIGS. 4 and 5).

The cylinder main body 11 has a plurality of valve chambers 24 formedtherein as is best shown in the cross-sectional views of FIGS. 6-8. Inparticular, eight separate valve chambers 24 are provided. The valvechambers 24 are divided into two groups A and B (FIG. 7) of four valvechambers 24 each. The two groups A and B of valve chambers 24 each forma row of adjacent valve chambers 24. The valve chambers 24 of group Aare air-inlet chambers and the valve chambers 24 of group B are exhaustchambers, as will become more apparent below. A bottom section of thevalve chambers 24 (i.e., adjacent the bottom surface 116) is shaped toconform to the shape of the rotary valve to be received therein.Passages 27, 28 extending between the end faces 17, 18 and through thevalve chambers of groups A, B, respectively, are formed in the main body11.

As will be described in more detail herein below, each valve chamber 24is shaped to accommodate two rotary valves 30 in a side-by-sidearrangement, for example, as shown in FIG. 7.

Insertion passages 32 are provided in the cylinder main body 11 of thecylinder head 7 extending between each of the valve chambers 24 and thetop surface 15. As may be best seen in FIG. 3, each of the passages 32defines a generally heart-shaped opening 33 in the top surface 15. Eachopening 33 and insertion passage 32 is sized to allow a rotary valve 30to be inserted therethrough into the associated valve chamber 24. Eachinsertion passage 32 widens from its respective opening towards itsrespective valve chamber 24 in a longitudinal direction (see FIG. 6),but has a constant width in a direction normal to the longitudinaldirection (see FIG. 8).

Flow passages 36 are provided in the main body 11 extending between eachvalve chamber 24 and the bottom surface 16. Two flow passages 36 areprovided between each valve chamber 24 and the bottom surface 16 (onefor each rotary valve to be accommodated therein). In particular, theflow passages 36 extend between the valve chambers 24 and recesses 38formed in the bottom surface of the main body 11. In the exemplarycylinder head 7, four recesses 38 are formed. The recesses 38 are sizedto correspond to the cylinders formed in the engine main body and arearranged to be aligned therewith. The recesses 38 form so-called flamefaces for the cylinders in the engine main body. Each recess 38 isfluidly connected to two separate valve chambers 24, one valve chamber24 of group A and one valve chamber 24 of group B. Each of the flowpassages 36 defines an opening 39 in one of the spherical recessions 38.Each flow passage 36 tapers from its respective valve chamber 24 towardsthe corresponding opening 39.

In several of the figures, it can be seen that certain of the flowpassages 36 and their corresponding openings 39 towards the sphericalrecessions 38 are of a different size to others. The reason for thesedifferent sizes being that the flow passages 36 having smallerdimensions are shown in a pre-finished state, such as a cast state. Theflow passages 36, however, having larger dimensions are shown in afinished state. It should be noted that only the valve chambers 24having the rotary valves 30 shown therein are shown in a finished state.The other valve chambers 24 (and passages 36), however, will be similarto those having the rotary valves 30 therein, once they are finished.

The insertion passages 32 and the flow passages 36 are arranged in theengine main body 11 such that there is a substantially straight line ofaccess through the insertion passages 32 towards the flow passages 36.Circular sealing arrangements 44 are provided within each valve chamber24 (once they are finished). The circular sealing arrangements arearranged such that they surround each opening of the passage 36 towardsthe valve chamber 24 and are arranged coaxially thereto. Each sealingarrangement 44 is accommodated in a corresponding seat, machined into asurface of the valve chamber surrounding each passage 36 (see FIG. 6).

A longitudinally extending air-duct 47 is provided in the exemplary mainbody 11. The air-duct 47 is open towards the end face 18 at opening 48.The opening 48 may be closed by a cover (not shown), when the cylinderhead 7 is assembled. Passages 49 and 50 are provided which extendbetween the air-duct 47 and the top surface 15. The air-duct 47 extendsadjacent the side 19 of the main body. In the area of the air-duct 47,the bottom surface 16 is recessed.

A flow passage 55 is provided between each valve chamber 24 of group Aof the valve chambers 24 and air-duct 47. The flow area of the flowpassage 55 is larger than the combined flow area of the flow passages 36associated with the valve chamber 24 to which the flow passage 55 isconnected. Also, the flow area of the air-duct 47 is larger than theflow area of the flow passage 55.

An exhaust passage 60 is provided between each valve chamber 24 of groupB and the side 20 of the main body 11. Each exhaust passage 60 openstowards the side 20 of the cylinder main body 11 at a correspondingopening 62. The flow passages 60 each taper from their correspondingvalve chamber 24 towards the side 20 of the main body. The flow area ofthe flow passage 60 at the opening 62, however, is larger than thecombined flow area of the flow passages 32 associated with one of thevalve chambers of group B.

The cylinder main body 11 also has mounting holes 65 extending betweenthe top surface 15 and the bottom surface 16. At the top surface 15, themounting holes 65 have an enlarged diameter to allow the head of amounting bolt to be received therein.

The cylinder main body 11 also has injector passages 67 which extendbetween the top surface 15 and the bottom surface 16 thereof. Theinjector passages are each arranged to open in the center of one of thespherical recessions 38 formed in the bottom surface 16 of the main body11. The injector passages 67 extend through a part of the main bodywhich separates the group A of the valve chambers 24 from the group B.As is best shown in FIG. 8, the injector passage has multiple stepsdecreasing in diameter from the top surface 15 towards the bottomsurface 16 of the main body 11. Similarly, the wall portion separatingthe two valve chambers 24 of groups A and B also decreases in width fromthe top surface 15 towards the bottom surface 16. Further, mountingholes 69 and 70 are provided in the top surface 15. The mounting holes69 and 70 are provided with internal threads. The mounting holes 70 arearranged on a line with the injector passages 67.

The top surface 15 has a recessed main part of a rectangular shape. Therecessed main part has a finished surface to allow sealing to the coverplate 12, as will be described below. The insertion openings 33, themounting holes 65, the injector passages 67, and the mounting holes 69and 70 are each formed in the recessed main part of the top surface 15.The top surface 15 also has a finished flat surface surrounding each ofthe passages 49 and 50, to allow sealing to air supply ducts, as will bedescribed in more detail below.

The bottom surface 16 has a finished flat main surface for sealing tothe engine main body. Outside of the sealing surface, the sphericalrecessions 38 and the recess 53 are provided.

The side 20 of the cylinder main body 11 also has finished flatsurfaces, at least around the openings 62 of the flow passages 60, toallow sealing to an exhaust manifold.

The cover plate 12 is a substantially flat rectangular plate. The coverplate 12 is dimensioned to sit in the recessed main part of the topsurface 15 of the main body 11. The cover plate 12 has a top surface 80and a bottom surface 82. The bottom surface 82 is a flat finishedsurface, to allow sealing to the recessed main part of the top surface15 of the main body 11. Even though not shown, a sealing arrangement maybe arranged between the cover plate 12 and the cylinder head 7, whenmounted thereon.

The cover plate 12 has a plurality of mounting holes 84 extendingbetween its top surface 80 and its bottom surface 82. The number ofmounting holes 84 and their arrangement corresponds to the number andarrangement of mounting holes 69 and 70 formed in the top surface 15 ofthe main body 11. The cover plate 12 also has openings 86 extendingbetween the top and bottom surface thereof. The openings 86 are sized toaccommodate part of an injector arrangement (not shown) therein. Theopenings 86 are arranged such that they are aligned with the injectorpassages 67 in the main body 11, when the cover plate 12 is mountedthereon.

Having described above an exemplary cylinder head 7, it should be notedthat the application is not limited to the specific cylinder headconfiguration. In particular, as mentioned above, the valve chamber 24is shaped to receive two rotary valves 30 therein. The valve chamber 24,however, may be shaped to receive a single rotary valve or a largernumber than two rotary valves 30 therein. Furthermore, if two or morerotary valves 30 are used, these do not necessarily have to be arrangedin a side-by-side arrangement as shown.

Independent of the number of rotary valves 30 per valve chamber 24, theseveral passages arranged within the cylinder head 7 may remain thesame. Only the number of flow passages 36 might be adapted. Furthermore,the cylinder head 7 as shown is configured to serve four cylinders of aninternal combustion engine. The cylinder head 7 may, however, be adaptedto serve any number of cylinders. Especially in large engineapplications, one cylinder head may be provided per cylinder of theengine.

Even though the cylinder main body 11 of the cylinder head 7 is shown asa single piece cylinder main body 11 having valve chambers 24 formedtherein, the cylinder main body 11 could include two or more body parts,such as an upper and a lower body part, which when assembled form thevalve chambers 24 and the respective flow passages. In such a splitdesign, the insertion openings 32 may be dispensed, as cylinders may beinserted into the valve chambers 24 before assembly of the body parts.For the same reason, the cover plate 12 could be dispensed.

Where the cover plate 12 is used to cover the insertion openings 32 inthe cylinder head 7, the surface of the cover plate 12 facing to thecylinder head 7 may not be flat. It may rather have one or moreprojections dimensioned to fit into the insertion passages 32 to atleast partially fill those. Apart from such projections, the surface ofthe cover plate 12 facing the cylinder head 7 may again be a flatfinished sealing surface.

Though not shown, cooling fluid passages may be arranged within thecylinder head main body 11 of the cylinder head 7. In particular, acooling fluid passage may be provided within an elevated wall portionbetween adjacent flow passages 36, adjacent each valve chamber 24, andin particular circumferentially around the longitudinally extendingpassages 27 and 28. In the one-piece design of the cylinder main body 11cooling fluid passages may extend substantially from the bottom to thetop of the one piece cylinder head main body 11.

In the example shown in FIG. 7, longitudinal passages 27, 28 areprovided in the cylinder head 7. It would also be possible to providepassages extending transverse in the valve body to accommodate a driveshaft therethrough. In such a case, the drive shaft would extend fromthe side portions of the cylinder head 7. The valve chamber 24 may beadapted accordingly and possibly the location of some of the flowpassages also may be adapted. Having passages for accommodating driveshafts extending transverse to the valve body may be an option in acylinder head configured for a single cylinder.

FIG. 10 shows schematically an end view of another exemplary cylinderhead 107. The cylinder head 107 has a cylinder head main body 111 havinga top surface 115, a bottom surface 116, end faces (only one of which isshown), and sides 119 and 120. Valve chambers 124 are provided withinthe cylinder head main body 111. The valve chamber 24 may be ofsubstantially the same shape as in the cylinder head 7 described above.The valve chamber 124 and other internal parts of the cylinder head mainbody 111, which will be described herein below, are indicated by brokenlines.

Longitudinal passages 127 and 128 extend between the end faces of thecylinder head main body 111. The passages 127, 128 are again arranged toextend through separate groups A, B of valve chambers 124. Rotary valves130 are schematically indicated, to be received in the valve chambers124. Passages 132 are provided in the cylinder head main body 111extending between each of the valve chamber 124 and the top surface 115.The bottom surface 116 again has recessions 138 and flow openingsbetween the individual valve chamber 124 and the recessions 138 areprovided as in the cylinder head 7, described with respect to FIGS. 1-9.An injector passage 67 is also provided between each recession 138 inthe bottom surface 116 and the top surface 115.

One major difference between the cylinder head 107 and the cylinder head7 described before is that no additional flow passages such as the flowpassages 47, 55, and 60 are provided. Fluid flow into or out of therespective valve chamber 124 is provided via the passage 132 which is acombined insertion/flow passage. Furthermore, the shape of the topsurface 115 differs from the shape of the top surface 15 describedbefore.

The top surface 115 of the cylinder head main body 111 has alongitudinally extending central portion 180 which is horizontallyarranged. A part 181 of the top surface 115 is angled with respect tothe central part 180 and extends between the central part 180 and theside 119. A further part 182 of the top surface 115 is also angled withrespect to the central part 180 and extends between the central part 180and the side 120.

Passages 132 extending from valve chambers 124 of group A open towardspart 181 of the top surface 115. Passages 132 extending from valvechambers 124 of group B open towards part 182 of the top surface 115.The passages 132 have a main extension which is substantially at rightangles to its respective part 181, 182. The parts 181 and 182 of the topsurface 115 are angled with the same angle with respect to the centralpart 180. The part 181 is arranged with respect to the sphericalrecession 138 in the bottom surface 116, such that a plane parallel tothe part 181 may be tangential to the spherical recession 138 in thearea of the valve chamber. The same is true for part 182.

The cylinder head 107 may thus be formed symmetrical with respect to alongitudinal plane extending normal and through the center of part 180of the top surface 115. The parts 181 and 182 are each substantiallyflat and are finished in order to allow a sealing to respective flowmanifolds (not shown) to be mounted thereon and sealed therewith.Respective mounting holes (not shown) are provided in each of the parts181 and 182 of the top surface 115.

Even though the top surface 115 described above has a central part andtwo angled parts, it would be possible to dispense with the central part180 and just to have two angled parts. The angled parts would be angledwith respect to each other and with respect to the bottom surface of thecylinder head 107. An angle included between angled part 181 or angledpart 182 is for example in a range between 20 to 50 degrees or in arange between 30 to 40 degrees.

As mentioned above, each of the valve chambers 24 or 124 of the cylinderhead 7 or 107 is shaped to accommodate two rotary valves 30 therein, butmay also be shaped to accommodate a single rotary valve or more thantwo.

An exemplary rotary valve 30 will now be described in more detail withreference to FIGS. 11-16. The rotary valve 30 according to theembodiment shown in FIGS. 11-16 has a body 202 which is made, forexample, of a metal, a ceramic or a combination thereof, in the shape ofa spherical segment. The body has a spherical zone 204 and two parallel,generally flat side portions 206 and 208. The side portions 206, 208 areequidistant from a midpoint of the spherical zone 204.

The spherical zone 204 is generally rotationally symmetric with respectto an axis of rotation of the rotary valve 30. Any openings provided inthe spherical zone 204 are not considered to break this rotationalsymmetry even if these openings are not arranged in a rotationallysymmetric manner. As used herein, if reference is made to a rotationalsymmetry of an element or a portion thereof, the rotational symmetryrefers to the element or portion in general, disregarding any openingsformed in that element or portion, which may break the rotationalsymmetry.

A straight passage 210 is formed through the body 202 between the sideportions 206 and 208. The passage 210 is co-axial to a central axisextending between the two side portions 206, 208, which defines the axisof rotation for the rotary valve 30. The passage 210 is dimensioned toallow a drive shaft to be inserted therethrough, as will be described inmore detail herein below.

The body 202 also has a chamber 212 formed therein. The chamber 212 isopen towards both side portions 206, 208 at respective openings 216,218. The openings 216, 218 are of the same shape and dimensions and, ascan be best seen in FIG. 15, each of the openings 216, 218 hasapproximately a C-shape, partially surrounding the central passage 210.Each openings 216, 218 may extend more than 180° in a direction ofrotation of the rotary valve 30.

Furthermore in the embodiment as shown, openings 226 and 228 areprovided in the spherical zone 204 to open the chamber 212 towards thespherical zone 204. The two openings 226, 228 are arranged in aside-by-side arrangement and are symmetrical with respect to a planeextending through the midpoint of the spherical zone and being parallelto both side portions 206, 208. A web 230 is formed between the openings226, 228. The openings 226, 228 are centered with respect to the chamber212 in a rotational direction of the rotary valve body, i.e., incircumferential direction. Openings 226, 228 each widen in a directionaway from the plane, which is parallel to the side portions 206, 208.Furthermore, each of openings 226, 228 define a curved, concave leadingedge 232 and a curved concave trailing edge 233 with respect to adirection of rotation of the valve. The shape of the concave leadingedge 232 and the concave trailing edge 233 conforms to a circumferentialshape of a flow passage formed in a cylinder head 107, i.e. if the flowpassage is round, the leading edge will have a round shape.

A cross-sectional flow area of the opening 216 in the side portion 206is equal to or larger than a cross-sectional flow area of the opening226. Similarly, a cross-sectional flow area of the opening 218 is equalto or larger than a cross-sectional flow area of the opening 228. Thechamber 212 defines a fluid connection between the openings 216, 218 inthe side portions and the openings 226, 228 in the spherical zone.

A wall portion of the valve body 202 separating the passage 210 from thechamber 212 has an opening 238 formed therethrough. The opening 238 isaligned and centered with respect to opening 228 in the spherical zone204. The wall portion 234 has a raised section 240 extending into thechamber 212 and surrounding the opening 238. The raised section 240defines a flat surface 242. A similar mounting hole may be providedaligned and centered with respect to opening 226.

The rotary valve 30 shown in FIGS. 11-16 has two side-by-side openingsin the spherical zone 204 thereof. It should be noted, that a singleopening (e.g., without the web 230) or a larger number of openings(i.e., more than two), may be provided in the spherical zone.Furthermore, the chamber 212, as shown, is open at both side portions206, 208. Again it should be noted that the chamber 212 might only beopen to one of the side portions. It is also possible to provide aseparating wall in the chamber 212 to provide two separate chambers,each connected to one of the side portions 206, 208 and one of theopenings 226, 228 in the spherical zone 204. Indeed, any type of fluidconnection between the openings 216, 218 in the side portions 206, 208and the openings 226, 228 in the spherical zone 204, such as a straightpassage may be provided in the valve body 202. Although the openings226, 228 in the spherical zone 204 are symmetrical with respect to aplane parallel to the side portions 206, 208 as shown, it is possible tooffset the two openings in a direction of rotation of the rotary valveor to have openings of different shapes and sizes. An annular protrusionmay be provided around the central passage to extend the passage beyondthe otherwise flat side portions 206, 208.

The rotary valve 30 was described as having a spherical zone 204, whichis rotationally symmetric with respect to the axis of rotation of therotary valve 30. Rather than having a spherical zone 204, it is possibleto provide a generally curved portion, which is rotationally symmetricwith respect to the axis of rotation of the rotary valve 30. In otherwords, the curvature of the surface extending between two side portionsin the direction of rotation may differ from the curvature perpendicularto the direction of rotation. The curvature perpendicular to thedirection of rotation may be circular or may deviate therefrom, forexample, an oval curvature. Although a convex (spherical) curvature isshown in the drawings, a concave curvature or a mixture of concave andconvex curvatures is possible. The curvature may be symmetric withrespect to a plane which is parallel to the side portions and bisectsthe rotary valve, but it is also possible to have a non-symmetricalcurvature.

As indicated by a broken line in FIGS. 11 and 16, opening 226 (and/or228) may have a part 250 which extends beyond at least one of theleading edge 232 and the trailing edge 233. This part 250 may be seen asa secondary part of the openings 226, 228. This secondary part wouldhave a cross-sectional flow area which is substantially smaller than theflow area of the rest of the opening. The part 250 would, for example,have a flow area which is less than 50 percent of the flow area of theother part of the openings 226 and 228.

The interior surfaces of the chamber 212 and/or of the flow passages oropenings 260, 276, 278 in the rotary valve may be made of a heatinsulative material. In particular, a coating may be provided on thesesurfaces. Additionally, heat insulative material may be provided on anysurface of the rotary valve, including the central passage. The wholedeflector may indeed be made of a heat insulative material.

FIG. 17 shows a cross-sectional view (similar to FIG. 14) of analternative rotary valve 30. The rotary valve 30 shown in FIG. 17 hasall the features of the rotary valve 30 described with respect to FIGS.11-16. The only difference is that an additional opening 260 extendingbetween the chamber 212 and the spherical zone 204 is provided. Theadditional opening 260 is rotationally offset with respect to theopenings 226, 228. The flow area of the additional opening 260 issmaller than the combined flow area of the openings 226, 228. Ratherthan providing a single additional opening 260 between the chamber 212and the spherical zone, several additional openings 260 may be provided.These can be in a side-by-side arrangement similar to the openings 226,228 or they can be rotationally offset. The combined flow areas of theopenings 260 are smaller than the combined flow areas of openings 226,228. The openings 226, 228 and 260 may be seen as a set of openings. Inan alternative rotary valve, a second set of these openings which isrotationally offset by 180° may be provided. In this case, the chamber212 would have to be adapted accordingly.

FIG. 18 shows a cross-sectional view (similar to FIG. 12) of yet anotherexemplary rotary valve 30. The rotary valve 30 shown in FIG. 18 hassubstantially the same features as the rotary valve 30 described withrespect to FIGS. 11-16. The rotary valve 30 according to FIG. 18,however, differs from the rotary valve 30 shown in FIGS. 11-16 by havingadditional flow passages 276 and 278 formed in the body 202 thereof. Theflow passages 276, 278 extend between the spherical zone 204 and theside portions 206, 208 respectively and define respective openings 296,298, 286, and 288. The flow passages are each angled with respect to theside portions 206, 208.

Even though FIG. 18 shows the flow passages 276, 278 being symmetricwith respect to a plane, which is parallel to the side portions 206, 208and bisects the rotary valve, they may be asymmetric. Rather than havingtwo flow passages 278, 288, a single flow passage may be provided.Furthermore, a larger number of flow passages may be provided, which maybe symmetrically paired, like the ones in the drawings, or which may beasymmetric such as offset with respect to the direction of rotation ofthe rotary valve.

FIG. 19 shows a schematic longitudinal cross-sectional view of a driveshaft 300 for rotating rotary valves mounted thereon. The drive shaft300 is, for example, suitable to be used with the cylinder head 7 andthe rotary valves 30, as described above, and reference may be madethereto. The drive shaft 300 is dimensioned to pass through the passages27, 28 of cylinder head 7 and any bearing elements provided therein. Thedrive shaft 300 is made of metal, ceramic, or any other suitablematerial.

The drive shaft 300 has a central flow passage 305 extendinglongitudinally therethrough, which may be connected to a cooling fluidsupply (not shown). Especially in the case of a drive shaft made ofceramic, the flow passage may be dispensed with. The drive shaft 300 hasa plurality of mounting holes 310 formed therein, each mounting holebeing provided for mounting of a rotary valve to the drive shaft 300, aswill be explained in more detail herein below. The mounting holes 310are spaced in a longitudinal direction. As shown in FIG. 19, theexemplary drive shaft 300 has eight mounting holes 310 formed therein.The first two mounting holes 310 on the left hand side of the driveshaft 300 are formed in the same angular position with respect to therotational direction of the drive shaft 300. The first two mountingholes 310 form a first group 312 of mounting holes 310.

The third and fourth mounting holes 310 form a second group 314, thefifth and sixth mounting holes 310 (which are indicated by a brokenline) form a third group 316 and the seventh and eighth mounting holes310 (which are indicated by a broken line) form a forth group 318. Themounting holes 310 are rotationally aligned within in each group 312 to318, but rotationally offset with respect to the mounting holes of theother groups. In the example shown in FIG. 19, each group 312 to 318 isrotationally offset by 90° with respect to two of the other groups and180° with respect to one of the groups. The centers of the mountingholes 310 in each of the groups are spaced with a distance correspondingto the distance between adjacent flow passages 36 in the above describedvalve chambers 24. Adjacent mounting holes of adjacent groups are spacedwith a distance corresponding to the distance between adjacent flowpassages 36 of adjacent valve chambers 24.

The mounting holes 310 are stepped holes having an outer portion 320 andan inner portion 322. The outer portion 320 has a larger diameter thanthe inner portion 322. The inner portion 322 has an internal thread.Although the drive shaft 30 was described for use with the specificcylinder head and the rotary valves shown above, the number of mountingholes and their relative positions may vary in different applications.Depending on the application, more than two mounting holes 310 may beprovided in each group, for example, when more rotary valves are to begrouped together per group or when more than one mounting hole is usedto mount a rotary valve on the drive shaft. The rotary valves may berotationally aligned within the groups or rotationally offset with apredetermined angle.

FIG. 20 shows an enlarged sectional view of a rotary valve 30 asdescribed with respect to FIGS. 11-16 mounted onto the drive shaft 300.As can be seen in FIG. 20, a ring dowel 330 is provided, extending intothe opening 238 of the rotary valve 30 and into the outer portion 320 ofthe mounting hole 310 in the drive shaft 300. The ring dowel may be madefrom metal or any material which is strong enough to withstand thestress applied thereto. Furthermore, a screw 335 having a head and ashaft is provided. The shaft extends through the ring dowel 330 into theinner part 322 of the mounting hole 310 where external threads on theshaft come into engagement with the inner threads provided in part 322of mounting hole 310. The lower part of the head of the screw 335 is inengagement with the flat surface 242 of the raised section 240 of therotary valve 30.

FIGS. 21 (a) and (b) show different examples of a deflector/bearingassembly 400 to be arranged within the cylinder head 7 as, for example,shown in FIG. 6 and reference may be made thereto. The deflector/bearingassembly 400 has a bearing part 402 and a deflector part 404. Thebearing part 402 is formed by an inner race 406, an outer race 408, anda plurality of bearing elements interposed therebetween, such as rollersor balls. Also, any other type of bearing element may be used.Lubrication in the form of a lubricant is provided for the bearingelements and end plates 410 and 412 are provided to seal the lubricantinto the bearing part 402. The inner and outer race 406, 408 and/orbearing part 402 may have a surface made of a solid lubricant, in whichcase sealing of a viscous lubricant is not required. The inner race 406has a central opening 414 dimensioned to accommodate the drive shaft 300therein.

The deflector part 404 is formed of a one piece deflector body 420. Thedeflector body 420 has a central opening 424 extending longitudinallytherethrough. The central opening 424 is dimensioned to accommodate thedrive shaft 300 therein. The deflector body 402 is rotationallysymmetrical with respect to a central axis of the central opening 424.The deflector body 402 has a diameter which is approximately equal to orlarger than a diameter of one of the passages 27, 28 formed in thecylinder head 7.

The deflector body 420 has a substantially flat surface 426 facing thebearing part 402. A deviation from the flat surface is an annularprojection surrounding the central opening 424. The annular projection428 is dimensioned to come into engagement with the inner race 406 ofthe bearing part 402. When the annular projection 428 is in engagementwith the inner race 406, the flat surface 426 is spaced from the rest ofthe bearing part 402.

The deflector body 420 also defines a deflecting surface 430 facing awayfrom the flat surface 426. The deflecting surface 430 decreases indiameter in a direction away from the flat surface 426 and defines acurve. At the end of the deflector body 420, which is opposite to theannular projection 428, a flat abutment surface 432 is formed forengagement with a part of the rotary valve 30 surrounding the passage210, for example, as shown in FIG. 6.

In FIG. 21 (a), the deflector body and the inner race are shown to beseparate parts. As shown in FIG. 21 (b) the deflector body 420 and theinner race 406 may be formed as a single piece. Although FIG. 21 (a)shows the deflector part and the bearing as an assembly, it should benoted that the deflector part and the bearing may indeed be usedindependently from each other, i.e. a deflector part as shown anddescribed may be used as a deflector independently of the presence of abearing part and vice versa. The bearing part may, for example, bedispensed with if a rotary shaft (such as drive shaft 300) and a passage(such as passage 27 or 28) are configured to have complementary bearingsurfaces formed thereon. Such complementary bearing surfaces could, forexample, be surfaces made of a solid lubricant. In such an arrangementat least one of a surface of the drive shaft and an inner wall surfaceof the passage should be made of a solid lubricant.

The deflecting surface 430 may be a smooth curving surface, as shown, orit may, for example, have guide grooves arranged therein. It is alsopossible that blades are provided on the deflector in lieu of or incombination with the deflecting surface. Such blades may be configuredto facilitate changing a longitudinal fluid flow (with respect to thedeflector) to a radial flow or vice versa, in particular upon rotationthereof. The deflecting surface and optionally the other surfaces of thedeflector may be made of a heat insulative material. The deflector bodyas a whole may be made of a heat insulative material or may, forexample, be made of metal at least partially coated with a heatinsulative material.

FIG. 22 shows an assembly of two deflectors, which may each besubstantially of the same shape and dimensions as the deflector part 404shown in FIG. 21 (a). The main difference is, however, that the annularprojection 428 is dispensed with so that the deflectors 450 can bearranged in a back-to-back relation as shown in FIG. 22 without forminga space therebetween. Such an assembly of deflectors may, for example,be used in combination with the cylinder head arrangement shown in FIG.6, where the assembly would be arranged between adjacent rotary valves30 in the same valve chamber 24. Although the deflectors 450 are shownas separate parts, they may be integrally formed, to form a deflectorhaving oppositely facing deflector surfaces.

FIG. 23 shows a schematic end view of an exemplary internal combustionengine 1, such as the one previously described. In particular, FIG. 23schematically shows a drive mechanism for driving rotary valves arrangedin the cylinder head 7 thereof. Reference numeral 500 indicates acrankshaft 500. Reference numerals 502 and 504 indicate a drive shaft,such as a drive shaft 300 described above and arranged in the cylinderhead 7.

Drive elements 512 and 514, such as, for example, belts, chains, toothedbelts, etc., are entrained about the crankshaft 500 and the drive shafts502, 504 respectively. Rotation of the crankshaft 500 is therebytransmitted to the drive shafts 502, 504, respectively. Though notshown, a reduction mechanism may be provided in order to ensure that onerotation of the crankshaft translates into half a rotation of each ofthe drive shafts 502, 504. Rather than having drive belts directlyentrained about the crankshaft 500 and the drive shafts 502, 504,pulleys may be coupled to these members, and the drive belts may extendaround the pulleys. Also, a gear mechanism having, for example circulargears may be used to transmit rotation of the crankshaft 500 to thedrive shafts 502, 504.

FIG. 24( a) shows a schematic end view of an alternative internalcombustion engine, and FIG. 24( b) shows a schematic top view thereof.The internal combustion engine may be the same as the one describedabove with respect to FIG. 1. The drive mechanism, however, differs withrespect to the previously described drive mechanism. In the drivemechanism according to FIG. 23, the drive shafts 502, 504 was directlycoupled by a corresponding drive elements 512, 514 to each of the driveshafts 502, 504. In the Example, as shown in FIGS. 24( a) and 24(b),however, the crankshaft 500 is only directly coupled to drive shaft 504via the drive element 514. A separate drive element 520 is providedwhich is entrained about the drive shafts 502 and 504 to transmitrotation of drive shaft 504 to drive shaft 502. The crankshaft 500 isthus rotatably coupled to the drive shaft 502 via the drive shaft 504and the drive elements 514, 520. The drive elements 514 and 520 areprovided at opposite ends of the drive shaft 504.

FIG. 25 shows an end view of another exemplary internal combustionengine 1, such as the one described above. The end view shows yetanother alternative drive mechanism for transmitting rotation of acrankshaft 500 to drive shafts 502, 504. The drive mechanism has arotatable shaft 530 which may, for example, be rotatably supported bythe cylinder head 7 of the internal combustion engine 1, or by any othermeans. An elliptical gear 532 is mounted on the rotatable shaft 530.Elliptical gears 534 and 536 are also mounted to driveshaft 502, 504,respectively. The elliptical gears 532, 534 and 536 are arranged suchthat they are in constant engagement. The elliptical gears 534 and 536are arranged on opposite sides of the elliptical gear 532. Furthermore,a drive belt 540 is provided which is entrained about the shaft 530 andthe crankshaft 500.

Although the example shown in FIG. 25 shows a very specific arrangementof elliptical gears, differently shaped elliptical gears may be used.Furthermore, a different arrangement of such elliptical gears may beused. For example, only two elliptical gears may used which would allowtransmitting rotation from the crankshaft 500 to one of the drive shafts502, 504. A drive mechanism may then be provided to rotatably couple thedrive shafts, similar to the setup shown in FIG. 24. Instead ofelliptical gears, it is also possible to provide one or more ellipticalpulleys and provide a drive element there around.

The characteristics of the elliptical gears or pulleys are that on aconstant rotation of one of the elements, the other element will have avarying speed. The speed will vary between a slow and a fast speed.During a single rotation of one elliptical element (such as the oneshown), with a constant rotational speed, the other element will havetwo phases at which it will rotate with a slow speed and two phases atwhich it will rotate with a fast speed. Depending on the speed changesrequired during a single rotation, multi-lobe elliptical gears orpulleys may be used.

In general, any two non-circular elements, one rotatably coupled to adrive source, such as the crankshaft (as shown in FIG. 25( a)) and theother rotatably coupled to the drive shaft and which are coupled tocause the above speed variation may be used. The above described speedvariation may also be achieved, if an elliptical or non-circular elementis coupled to a circular element. In the case of a non-circular pulleycoupled to a circular pulley, belt tensioning may be provided to take upany slack occurring during the rotation of the pulleys. If anon-circular gear is used in combination with a circular gear, amechanism may be provided which allows relative movement between theelements. Such a relative movement allows the distance between thecenters of rotation of the gears to vary during rotation of the gears.Such a mechanism may also be used for the pulleys to provide belttensioning as described above.

FIG. 26 shows another alternative drive mechanism for drive shafts 502,504 arranged in a cylinder head 7 of an internal combustion engine 1.The drive mechanism includes an electric drive motor 550 attached to oneend face of the cylinder head 7. As can be seen in the different viewsof FIG. 26, the electric drive motor 550 is arranged such that the driveshaft 504 partially extends therein. As best seen in FIG. 26( c),permanent magnets 555 are embedded into the drive shaft 504. The part ofthe drive shaft 504 in which the permanent magnets 555 are embedded, issurrounded by a stator 560 of the electric motor. The drive shaft 504thus acts as a rotor of the drive motor 550.

A drive element 570 is provided which is entrained about the driveshafts 502, 504. The drive shaft is provided at an end of the driveshaft 504, which is opposite to the end, which is accommodated in theelectric drive motor 550.

FIG. 26( a) shows a sensor 580 for sensing the rotational position andspeed of the crankshaft 500. The detector 580 is connected to the drivemotor 550 to provide information with respect to the rotational positionand rotational speed of the crankshaft 500 to the drive motor 550.Alternative sensors, such as a piston position sensor, may be provided.Although the drive motor 550 was described as an electric drive motor, ahydraulic or pneumatic drive motor could be used instead. It is also notnecessary that the driveshaft 504 extends into the drive motor 550. Aregular drive motor having a rotor and a stator may be provided and therotor may be coupled to the drive shaft either within or outside of thedrive motor. A separate drive motor may be provided for each of thedrive shafts thereby eliminating the need of a drive element to transmitrotation between the drive shafts.

The drive motor 550 is arranged to act on the drive shaft 504, whichwill have rotary valves attached thereto. Rather than having a drivemotor 550 acting on a drive shaft, it would also be possible to providea drive motor which directly acts upon rotary valves accommodated withina cylinder head of an engine. In this case, the rotary valve may havepermanent magnets embedded therein, upon which a stator of the drivemotor may act. The rotary valves may be journalled on a respective shaftor could be provided on a shaft journalled within the cylinder head.Alternative means for journaling the rotary valves in the cylinder headmay be provided.

The stator of such a drive motor may, for example, be attached to thecover plate 12 and in particular to the protrusions described to extendinto the insertion passages 32. The stator of such a drive motor mayalso be formed by interior walls of the valve chamber for accommodatingthe rotary valve.

With respect to the drive mechanism described hereinbefore, combinationsthereof may be formed. It is for example possible to provide amechanical drive train including gears and/or pulleys between an outputof the drive motor and the drive shaft. In particular, non-circularelements may also be used in such a mechanical drive train coupling anoutput of the drive motor to one or both of the drive shafts.

INDUSTRIAL APPLICABILITY

The previously described cylinder head 7 and its associated parts may beused for any type of combustion engine, especially engines having directfuel injection. If no direct fuel injection is used, a fuel-air mixturemay be provided via the air-duct 47 and its associated valve chambers24. The cylinder head 7 may be a cast part having certain parts thereofmachined after the casting process. In particular, the flow passages 36,the sealing seats surrounding the flow passages 36, the passages 27, 28and the outside sealing surfaces may be typically machined.

In order to prepare the cylinder head 7 for use with an internalcombustion engine, the different parts associated therewith areassembled. Such an assembly will now be described with respect to FIG.6, showing a longitudinal cross section through the cylinder head 7.

The view according to FIG. 6 shows a cross section through group B ofthe valve chambers 24 and through passage 28. In the following,reference will thus be made to those valve chambers and to passage 28.Assembly of the valve chambers 24 and associated parts with respect togroup A will be performed in a similar manner.

In a first step, bearings will be arranged in the passage 28. Each partof the passage 28 being arranged between adjacent valve chambers 24 willreceive two bearings, such as bearings 402 therein. Additional bearings,which may be of the same shape and design, like the bearings 402, may bearranged in the parts of the passage 28 extending between the outermostvalve chambers 24 and the end faces 17, 18, respectively.

In a next step, deflectors, such as deflectors 404 will be arrangedadjacent the bearing received in the passage 28. The deflecting surfaceof the deflectors is arranged to face towards the inside of the valvechambers 24. Rather than having separate bearings and deflectors, anintegrated deflector bearing assembly as shown in FIG. 22 could be usedinstead.

In a next step, rotary valves, such as rotary valves 30, will beinserted into the valve chambers 24 through their respective insertionopening 32. Next, a drive shaft, such as drive shaft 300 will besubsequently inserted through bearings in the passage 28, a deflector404 in a first valve chamber 24, a first rotary valve 30 in the valvechamber, a second rotary valve 30 in the valve chamber, a seconddeflector 404 in the valve chamber, bearings in the passage etc. Duringthis assembly, the drive shaft may be cooled via its central coolingpassage to cause shrinking thereof, in order to allow a better insertionthrough the several parts of the assembly.

Once the drive shaft is inserted through all the parts of the assemblyand exits the opposite end of the cylinder head 7, the mounting holes310 in the drive shaft are aligned with the opening 238 in the rotaryvalves 30. This alignment will be observed through the insertion opening32 and will be performed in pairs. Once a opening 238 in a drive shaft30 is aligned with a corresponding mounting hole 310 in the drive shaft300, the dowel pin 330 is inserted through the opening 238 into the toppart of the mounting opening 310.

Finally, a screw 335 is inserted into the assembly and is screwed intothe inner part of the mounting hole 310 of the drive shaft 300.

In this manner, each of the rotary valves 30 is mounted to the driveshaft 300. As mentioned above, this final assembly of the rotary valves30 is done in pairs, as the groups 312 to 318 of mounting holes 310 arerotationally offset. Inasmuch as the alignment of the mounting holes andthe insertion of the dowel pin and the screw are performed through theinsertion opening 32, the rotary valves are kept in a constant position,and the drive shaft is to be rotated, to achieve alignment of themounting holes. It may also be possible to assemble the drive shaft andthe componentry associated therewith outside of the cylinder head and toinsert such an assembly through a corresponding passage formed eitherlongitudinally or transversely in the cylinder head. In a cylinder headof the split design such an assembly may be inserted before attachingthe separate body parts of the cylinder head to each other.

Once this assembly is completed, injectors may be mounted to thecylinder head 7 by inserting injectors through the correspondinginjector openings 67. Once the cylinder head 7 is pre-assembled in thismanner, it may be mounted to the engine main body, by bolts extendingthrough the mounting holes 65 into corresponding mounting holes in theengine main body.

Finally, the cover plate 12 may be placed onto the cylinder head 7 andattached thereto by bolts extending through the mounting holes 69 and70. Once the cylinder head 7 is mounted to the engine main body, a drivemechanism is coupled to the drive shafts. Furthermore, an exhaustmanifold is attached to side 20 of the cylinder head 7 to fluidlyconnect each of the passages 60 to the exhaust manifold. Similarly, airinlet pipes are connected to the top surface 15 of the cylinder head 7,to fluidly connect to passages 49 and 50 connected to the air-duct 47.The opening 48 in the end face 18 may be closed by a cover plate orplug. Alternatively, another air inlet pipe could be connected to endface 18, to provide airflow to the air-duct 47.

During operation of the engine, each of the rotary valves 30 willprovide successive opening and closing events for its corresponding flowpassage 36. The rotary valves 30 associated with group A of the valvechambers will mainly provide intake of air into the respective enginecylinders during an intake stroke and will prevent fluid flow into therespective valve chambers during a closing event. If an in-cylindercharge dilution (ICCD) is desired, i.e. a mixing of intake air withexhaust gas, for example aimed at reducing emissions such as nitrogenoxides (NOx) during combustion, a certain degree of gas flow from thecylinders to the valve chambers associated with group A may be provided.Such a gas flow may for example be provided by additional flow openings,such as flow opening 260 shown in FIG. 17 or flow openings 276 to 278shown in FIG. 18. It is also possible, that such a gas flow may beprovided by incomplete sealing between the sealing arrangement 44 andthe rotary valve 30 at least during a part of a rotation thereof. Suchan incomplete sealing could be achieved by providing sections in thespherical zone 204 of each rotary valve deviating from a rotationalsymmetry thereof.

Another alternative is to rotate each of the rotary valves 30 such thattwo opening events by the openings 226 to 228 occur during a singlecombustion cycle of the engine i.e. the rotary valve may make tworevolutions during a single combustion cycle. In this event, therotational speed of the rotary valves 30 could be varied, such that theopening events are of a different duration. In some embodiments a longerair intake opening duration may be used.

The rotary valves associated with group B of the valve chambers 24similarly provide opening events to exhaust gas from the respectivecylinders through the respective flow passages 36, the flow passage 226,228 in the rotary valves 30, into the respective valve chamber 24 andthrough the respective exhaust passage 60 to the exhaust manifold.

In order to achieve ICCD, rather than admitting exhaust gas into thevalve chambers 24 of group A, it is also possible to allow exhaust gasfrom the valve chamber 24 associated with group B to flow into therespective cylinders during an intake stroke. Such an air flow occurringoutside of the main opening event of the rotary valves for exhaustinggas from the cylinders, may occur in a similar manner as describedbefore. Additional flow openings 260 to 278 may be provided, incompletesealing between the rotary valves 30 and their corresponding sealingarrangement may be provided or the valves may be driven at a speed toachieve two or more separate valve opening events of the same openingsduring a single combustion cycle of the engine. Fuel may be injected viathe respective injectors in accordance with engine requirements.Alternatively a fuel-air mixture may be provided via valve chambers 24of group A.

The cylinder head 107 shown in FIG. 10 will be assembled in a similarmanner to the cylinder head 7, and operation thereof will be similar tothe one described before. The main difference lies in the fact that anair inlet manifold and an exhaust manifold will be attached to parts181, 182, respectively, of the top surface 115 of the cylinder head 107.Air will enter directly through the insertion opening 132 into therespective valve chambers 124 of group A rather than through an air-duct47 and flow passages 55. Similarly, exhaust gas will directly exit therespective valve chambers of group B through insertion openings 132 intothe exhaust manifold.

With respect to FIGS. 23 to 26 different drive arrangements are shown.In accordance with FIGS. 23 and 24, rotation of the crankshaft 500 ofthe engine 1 is transmitted directly via a mechanical drive train to therespective drive shafts 502, 504, arranged in the cylinder head 7. Themechanical drive train is designed such that a constant rotation of thecrankshaft 500 will translate into a constant rotation of the driveshafts 502, 504. Even though not shown, a speed reduction mechanism maybe provided, such that each of the drive shafts 502, 504 will run forexample at half speed of the crankshaft 500. In the case of rotaryvalves having two main flow passages there through, the rotational speedof each of the drive shafts 502, 504 may even be reduced to a quarterspeed of the crankshaft 500.

FIG. 25 shows an alternative mechanical drive train for transmittingrotation of the crankshaft 500 to the drive shaft 502, 504. Thismechanical drive train uses elliptical gears being in engagement witheach other. The elliptical gears have the effect, that upon a constantrotation of the crankshaft 500 the rotational speed of each of the driveshafts 502, 504 will vary between a low speed and a fast speed. Inproviding such a speed variation, for example, fast opening and closingof the rotary valves may be achieved. Even though FIG. 25 showselliptical gears of the bi-lobe type, multi-lobe elliptical gears may beused. Indeed, any type of non circular gear providing a speed variationsuch as the one described above could be used. The speed of the driveshaft will vary about a reference speed, which is associated with therotational speed of the source of rotation. The reference speed willdepend on the speed reduction mechanism, if any is used. Without a speedreduction mechanism, the reference speed will be equal to the speed ofrotation of the crankshaft.

Although FIG. 25 shows elliptical gears being in engagement, ellipticalpulleys being connected by drive belts could be used. They may producethe same effect. The elliptical gears shown in FIG. 25 will produceduring a single rotation of the crankshaft 500 two short periods, inwhich the rotary shafts 502, 504 are rotated at a high speed and twolonger periods, at which the rotary shafts 502, 504 rotate at a slowerspeed. Depending on the number of rotary valves attached to the driveshafts and the engine requirements, multi-lobe elliptical gears having adifferent number of speed changes may be used.

FIG. 26 shows an alternative drive mechanism for the drive shafts 502,504. In the example shown in FIG. 26, an electric drive motor is used todrive the drive shaft 504. Rotation of the drive shaft 504 is thentransmitted to the drive shaft 502 via a drive belt 570. A sensor 580,which detects the rotational position and speed of the crankshaft 500 isconnected to the drive motor 550, to transmit this information thereto.In accordance with this information, the drive motor 550 can rotate thedrive shafts 505, 502, respectively. The drive motor 550 may be drivenat varying speeds during a single rotation thereof. This may allow fastopening and closing of the rotary valve. The varying speeds may againvary about a reference speed associated with a crankshaft speed.

Rather than providing a drive motor 550 for one of the drive shafts andproviding a mechanical drive train between the drive shafts to couplethem together, two separate drive motors may be provided. This would addthe possibility to independently control rotation of each of the driveshafts. Especially in cases where a single rotary valve is attached tothe drive shaft, or where a drive shaft is associated with rotary valvesfor a single cylinder, individual tailoring of opening, closing and thespeed of rotation thereof is possible. In this way, the amount of fluidflow to and from the cylinder may be individually adjusted for thecylinder. Similar control is possible in the application where the drivemotor acts directly on the rotary valves, for example, when the rotaryvalves have magnets embedded therein, as described above. Such anindividual tailoring may be particular beneficial in combination with acorresponding tailoring of the amount of fuel to be injected.

An electronic control unit may be provided to control operation of thedrive motor. Even though FIG. 26 shows an electric drive motor,similarly a hydraulic drive motor may be provided.

The above description describes several examples for a cylinder head ofan internal combustion engine and its associated componentry. Thepresent application, however, is not limited to the specific examplesshown therein. Features of the different examples for the elements maybe combined and/or exchanged.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the system of the presentdisclosure. Other embodiments of the system will be apparent to thoseskilled in the art from consideration of the specification and practiceof the system disclosed herein. It is intended that the specificationand examples be considered as exemplary only, with a true scope beingindicated by the following claims and their equivalents.

1. A system for controlling fluid flow to or from a cylinder of aninternal combustion engine, the system comprising: first and seconddrive shafts having rotary valves mounted thereon; a cylinder headaccommodating the rotary valves and at least part of the drive shaftstherein, the rotary valves being arranged to selectively open or closeflow openings in the cylinder head; a source of rotation; and amechanical drive train rotatably coupling the source of rotation to thedrive shafts, the mechanical drive train including a first non-circularelement rotatably coupled to the source of rotation; a secondnon-circular element rotatably coupled to the first drive shaft; and athird non-circular element rotatably coupled to the second drive shaft;the first non-circular element being rotatably coupled to the second andthird non-circular elements to cause a speed variation in the second andthird non-circular elements upon a constant rotation of the firstnon-circular element; wherein the first, second, and third non-circularelements are elliptical gears.
 2. The system according to claim 1,wherein one of the non-circular elements is directly mounted onto thedrive shaft.
 3. The system according to claim 1, wherein the source ofrotation is a crankshaft of the internal combustion engine, which iscoupled to a piston reciprocally arranged in the cylinder.
 4. The systemaccording to claim 3, further including a non-circular element directlymounted onto the crankshaft.
 5. The system according to claim 1, whereina plurality of rotary valves are mounted to the drive shaft, each rotaryvalve being arranged to selectively open or close a respective one of aplurality of flow openings in the cylinder head.
 6. The system accordingto claim 1, wherein separate intake and exhaust rotary valves areprovided for controlling intake of fluid into and exhausting of fluidfrom the cylinder, respectively.
 7. The system according to claim 6,wherein the intake and exhaust rotary valves are mounted to differentdrive shafts.
 8. The system according to claim 1, wherein thenon-circular elements are rotatably coupled by one of a directengagement and a drive element entrained thereabout.
 9. The systemaccording to claim 1, wherein the non-circular elements are one ofbi-lobe elliptical gears and multi-lobe elliptical gears.
 10. The systemaccording to claim 1, wherein the mechanical drive train is configuredto cause the rotational speed of the shaft to vary about a referencespeed which is associated to the rotational speed of the source ofrotation.
 11. A method for controlling fluid flow to or from a cylinderof an internal combustion engine, the method comprising: rotating, witha source of rotation, at least two rotary valves accommodated in acylinder head associated with the cylinder, and being arranged toselectively open or close flow openings in the cylinder head; andvarying the speed of rotation of the rotary valves between at least twodifferent speeds during a single rotation thereof; wherein the rotatingof the rotary valves is performed by transmitting rotation from thesource of rotation to the rotary valves by a mechanical drive trainincluding a first noncircular element rotatably coupled to the source ofrotation; a second non-circular element rotatably coupled to a firstdrive shaft on which one of the at least two rotary valves is mounted;and a third non-circular element rotably coupled to a second drive shafton which one of the at least two rotary valves is mounted; the firstnon-circular element being rotatably coupled to the second and thirdnon-circular elements to cause a speed variation in the second and thirdnon-circular elements upon a constant rotation of the first non-circularelement; wherein the first, second, and third non-circular elements areelliptical gears.
 12. The method of claim 11, including varying thespeed of rotation of the at least two rotary valves about a referencespeed which is associated to a rotational speed of the source ofrotation.
 13. The method of claim 12, wherein the source of rotation isa crankshaft of the internal combustion engine and the reference speedis one of a fraction of the speed of rotation of the crankshaft, thespeed of rotation of the crankshaft, and a multiple of the speed ofrotation of the crankshaft.
 14. A system for controlling fluid flow toor from a cylinder of an internal combustion engine, the systemcomprising: a first drive shaft having a rotary valve mounted thereon; asecond drive shaft having a rotary valve mounted thereon; a cylinderhead accommodating the rotary valves and at least part of the driveshafts therein, the rotary valves being arranged to selectively open orclose flow openings in the cylinder head; a source of rotation; and amechanical drive train rotatably coupling the source of rotation to thedrive shaft, the mechanical drive train including a circular elementrotatably coupled to the source of rotation, a first non-circularelement rotatably coupled to the first drive shaft, a secondnon-circular element rotatably coupled to the second drive shaft, and athird non-circular element rotatably coupled to the circular element;wherein the third non-circular element is rotatably coupled to the firstand second non-circular elements to cause a speed variation in therotation of the first and second non-circular elements upon a constantrotation of the circular element; and wherein the first, second, andthird non-circular elements are elliptical gears.
 15. The system as setforth in claim 14, wherein at least one of the non-circular and circularelements is mounted in a manner that allows relative movement withrespect to the other circular or non-circular elements, such that adistance between respective centers of rotation of the non-circular andcircular elements may vary.